1. Field of the Invention
This invention relates to a portable, inexpensive means for instantaneously calibrating the flow of fluids from spray nozzles. It involves a device which may incorporate a gravity flowmeter connected by a hose which may be flexible to a pressure-fitting receptor for temporary connection by hand to fluid-disbursing nozzles such as are used in agriculture and industry.
2. Description of Related Art
An isolated gravity flowmeter designed for permanent mounting was described as early as 1932 by U.S. Pat. No. 1,889,705. Numerous variations of that basic device, including a gravity flowmeter similar in operation to that incorporated in the present invention, are well known and readily available. One such gravity flowmeter is described in U.S. Pat. No. 3,675,481. These flowmeters have not been used in a portable context, have not been used in conjunction with a hand-held receptor such as is described herein, and apparently have not been previously applied in the context of calibrating the flows from nozzles of agricultural and industrial spraying equipment.
One type of fluid-disbursing nozzle to which an application of the invention described herein is directed is the subject of U.S. Pat. No. 3,858,812. This nozzle is characteristic of a type of nozzle to which the present invention applies in that the end or face from which fluid is disbursed is irregularly shaped thus making it more difficult to create an acceptable seal between the nozzle to be calibrated and the receptor portion of the present invention. This irregular shape is characterized by surfaces whose planes are both perpendicular and parallel to the central direction that fluid is emitted from the nozzle.
A receptor for use in an unrelated context is described in U.S. Pat No. 809,792 as a pipe-coupling. This pipe-coupling is designed to itself grip the smooth discharge ends of faucets in a manner in which the pressure of liquid in the casing aids the grip of the pipe-coupling. Not only is the pipe-coupling designed for connection to smooth discharge ends of faucets, but it also is designed to retain itself to the faucet.
Prior to the present invention, it has been the traditional technique to calibrate nozzles by simply measuring the amount of fluid sprayed over a period of time such as 15 seconds to as much as 5 minutes. While this technique is simple to accomplish, it has the distinct disadvantages of being relatively slow and of requiring longer periods of time for nozzles designed for lower flow rates. These limitations have long been recognized and yet prior to the present invention, an inexpensive, accurate alternative has not been available. This has been despite a recognition by those skilled in the art that by far the biggest factor in misapplying agricultural chemicals--a problem which has been estimated to cost farmers a billion dollars a year--is calibration error in equipment. While efforts have been made to alleviate the problem of calibrating equipment accurately, efforts by those skilled in the art have been directed toward increasingly complex and expensive electronic monitoring and control devices. Of considerable concern in this regard has been the ability to avoid the introduction of error in the connection of any calibration device to the nozzle to be calibrated. Such error is frequently the result of the admission of outside air into the device or the leakage of fluid from the device at the connection to the nozzle. The receptor described herein permits an unexpectedly good connection to the nozzle to be calibrated in that it neither admits a significant amount of outside air nor leaks a significant amount of fluid. This allows readings with accuracy previously unavailable by simple, inexpensive devices.